Set Appliance State:

Mains Power Off
CH Demand
CH/HW switch in CH position
boiler On/Off switch ON
Ensure boiler is not in Pre-heat mode
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Observation:

Ensure that the CH thermostatic valve is quiet in its operation and that both its inlet and outlet pipes are hot, indicating that water is flowing through it correctly.